1. Field of the Invention
The present invention relates to a liquid electrophotographic printer, and more particularly, to a liquid electrophotographic printer having a recovery unit for recovering a liquid carrier from a drying roller in contact with a photoreceptor.
2. Description of the Related Art
In general, in a liquid electrophotographic printer such as a laser printer, an electrostatic latent image is formed on a photoreceptor such as a photoreceptor drum or a photoreceptor belt, developed using a toner having a predetermined color, and transferred to a sheet of paper, thereby obtaining a desired image.
The laser printer is largely classified into a liquid type and a dry type according to the toner used therein. The liquid-type laser printer employs a developer liquid containing a toner mixed with a volatile liquid carrier. The liquid-type laser printer exhibits better printing quality than the dry-type laser printer. Also, the liquid-type printer can prevent problems associated with using the hazardous toner powder. Thus, the liquid-type laser printer is increasingly used.
Referring to FIG. 1, a conventional liquid electrophotographic printer 100 includes a circulating photoreceptor belt 110 supported by a roller 112, a development station 120 installed directly under the photoreceptor belt 110, and a drying station 130 for recovering the liquid carrier supplied to the photoreceptor belt 110.
A developer liquid composed of toner having a predetermined color and liquid carrier is contained in the development station 120. The development station 120 also includes a developing roller 121, a cleaning roller 122 and squeegee rollers 123 and 124.
The developing roller 121 applies the developer liquid supplied from a developer liquid supplier 125 to the electrostatic latent image formed on the photoreceptor belt 110 by a laser scanning unit 111. The cleaning roller 122 removes the developer liquid remaining on the developing roller 121.
The squeegee rollers 123 and 124 remove the excess developer liquid from the photoreceptor belt 110 after the developer liquid is utilized for developing the electrostatic latent image. The removed developer liquid is induced by blades 126 and 127 and withdrawn into the development station 120.
Subsequently, the liquid carrier contained in the developer liquid sticking to the photoreceptor belt 110 is removed by the drying station 130. The drying station 130 includes a drying roller 131 pressed by the roller 112 and rotating in contact with the photoreceptor belt 110, a plurality of heating rollers 132 rotating in contact with the drying roller 131, and a collecting case 133.
An oleophilic absorption layer 131a provided on the surface of the drying roller 131 absorbs the liquid carrier remaining on the photoreceptor belt 110.
A halogen lamp 134 is provided within each of the heating rollers 132. The surface of the drying roller 131 is heated using the heat generated from the halogen lamp 134, thereby evaporating the liquid carrier absorbed into the absorption layer 131a. The evaporated liquid carrier is collected in the collecting case 133 and liquefied in a liquefaction device (not shown) for recycling. Finally, only the toner corresponding to the development image remains on the surface of the photoreceptor 110.
However, since the drying station 130 evaporates the liquid carrier remaining on the surface of the photoreceptor 110 to then recover the same in a gaseous state, a large amount of liquid carrier cannot be sufficiently removed. Particularly, excess developer liquid is not sufficiently removed from the squeegee rollers 123 and 124 of the development station 120, thereby further degrading the recovery efficiency of the liquid carrier.